<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
    "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta name="generator" content="AsciiDoc 8.2.2" />
<style type="text/css">
/* Debug borders */
p, li, dt, dd, div, pre, h1, h2, h3, h4, h5, h6 {
/*
  border: 1px solid red;
*/
}

body {
  margin: 1em 5% 1em 5%;
}

a {
  color: blue;
  text-decoration: underline;
}
a:visited {
  color: fuchsia;
}

em {
  font-style: italic;
}

strong {
  font-weight: bold;
}

tt {
  color: navy;
}

h1, h2, h3, h4, h5, h6 {
  color: #527bbd;
  font-family: sans-serif;
  margin-top: 1.2em;
  margin-bottom: 0.5em;
  line-height: 1.3;
}

h1 {
  border-bottom: 2px solid silver;
}
h2 {
  border-bottom: 2px solid silver;
  padding-top: 0.5em;
}

div.sectionbody {
  font-family: serif;
  margin-left: 0;
}

hr {
  border: 1px solid silver;
}

p {
  margin-top: 0.5em;
  margin-bottom: 0.5em;
}

pre {
  padding: 0;
  margin: 0;
}

span#author {
  color: #527bbd;
  font-family: sans-serif;
  font-weight: bold;
  font-size: 1.1em;
}
span#email {
}
span#revision {
  font-family: sans-serif;
}

div#footer {
  font-family: sans-serif;
  font-size: small;
  border-top: 2px solid silver;
  padding-top: 0.5em;
  margin-top: 4.0em;
}
div#footer-text {
  float: left;
  padding-bottom: 0.5em;
}
div#footer-badges {
  float: right;
  padding-bottom: 0.5em;
}

div#preamble,
div.tableblock, div.imageblock, div.exampleblock, div.verseblock,
div.quoteblock, div.literalblock, div.listingblock, div.sidebarblock,
div.admonitionblock {
  margin-right: 10%;
  margin-top: 1.5em;
  margin-bottom: 1.5em;
}
div.admonitionblock {
  margin-top: 2.5em;
  margin-bottom: 2.5em;
}

div.content { /* Block element content. */
  padding: 0;
}

/* Block element titles. */
div.title, caption.title {
  font-family: sans-serif;
  font-weight: bold;
  text-align: left;
  margin-top: 1.0em;
  margin-bottom: 0.5em;
}
div.title + * {
  margin-top: 0;
}

td div.title:first-child {
  margin-top: 0.0em;
}
div.content div.title:first-child {
  margin-top: 0.0em;
}
div.content + div.title {
  margin-top: 0.0em;
}

div.sidebarblock > div.content {
  background: #ffffee;
  border: 1px solid silver;
  padding: 0.5em;
}

div.listingblock {
  margin-right: 0%;
}
div.listingblock > div.content {
  border: 1px solid silver;
  background: #f4f4f4;
  padding: 0.5em;
}

div.quoteblock > div.content {
  padding-left: 2.0em;
}

div.attribution {
  text-align: right;
}
div.verseblock + div.attribution {
  text-align: left;
}

div.admonitionblock .icon {
  vertical-align: top;
  font-size: 1.1em;
  font-weight: bold;
  text-decoration: underline;
  color: #527bbd;
  padding-right: 0.5em;
}
div.admonitionblock td.content {
  padding-left: 0.5em;
  border-left: 2px solid silver;
}

div.exampleblock > div.content {
  border-left: 2px solid silver;
  padding: 0.5em;
}

div.verseblock div.content {
  white-space: pre;
}

div.imageblock div.content { padding-left: 0; }
div.imageblock img { border: 1px solid silver; }
span.image img { border-style: none; }

dl {
  margin-top: 0.8em;
  margin-bottom: 0.8em;
}
dt {
  margin-top: 0.5em;
  margin-bottom: 0;
  font-style: italic;
}
dd > *:first-child {
  margin-top: 0;
}

ul, ol {
    list-style-position: outside;
}
ol.olist2 {
  list-style-type: lower-alpha;
}

div.tableblock > table {
  border: 3px solid #527bbd;
}
thead {
  font-family: sans-serif;
  font-weight: bold;
}
tfoot {
  font-weight: bold;
}

div.hlist {
  margin-top: 0.8em;
  margin-bottom: 0.8em;
}
div.hlist td {
  padding-bottom: 5px;
}
td.hlist1 {
  vertical-align: top;
  font-style: italic;
  padding-right: 0.8em;
}
td.hlist2 {
  vertical-align: top;
}

@media print {
  div#footer-badges { display: none; }
}

div#toctitle {
  color: #527bbd;
  font-family: sans-serif;
  font-size: 1.1em;
  font-weight: bold;
  margin-top: 1.0em;
  margin-bottom: 0.1em;
}

div.toclevel1, div.toclevel2, div.toclevel3, div.toclevel4 {
  margin-top: 0;
  margin-bottom: 0;
}
div.toclevel2 {
  margin-left: 2em;
  font-size: 0.9em;
}
div.toclevel3 {
  margin-left: 4em;
  font-size: 0.9em;
}
div.toclevel4 {
  margin-left: 6em;
  font-size: 0.9em;
}
/* Workarounds for IE6's broken and incomplete CSS2. */

div.sidebar-content {
  background: #ffffee;
  border: 1px solid silver;
  padding: 0.5em;
}
div.sidebar-title, div.image-title {
  font-family: sans-serif;
  font-weight: bold;
  margin-top: 0.0em;
  margin-bottom: 0.5em;
}

div.listingblock div.content {
  border: 1px solid silver;
  background: #f4f4f4;
  padding: 0.5em;
}

div.quoteblock-content {
  padding-left: 2.0em;
}

div.exampleblock-content {
  border-left: 2px solid silver;
  padding-left: 0.5em;
}

/* IE6 sets dynamically generated links as visited. */
div#toc a:visited { color: blue; }
</style>
<script type="text/javascript">
/*<![CDATA[*/
window.onload = function(){generateToc(2)}
/* Author: Mihai Bazon, September 2002
 * http://students.infoiasi.ro/~mishoo
 *
 * Table Of Content generator
 * Version: 0.4.sp
 *
 * Feel free to use this script under the terms of the GNU General Public
 * License, as long as you do not remove or alter this notice.
 */

 /* modified by Troy D. Hanson, September 2006. License: GPL */
 /* modified by Stuart Rackham, October 2006. License: GPL */
 /* modified by Shawn Pearce, August 2009. License: GPL */

function getText(el) {
  var text = "";
  for (var i = el.firstChild; i != null; i = i.nextSibling) {
    if (i.nodeType == 3 /* Node.TEXT_NODE */) // IE doesn't speak constants.
      text += i.data;
    else if (i.firstChild != null)
      text += getText(i);
  }
  return text;
}

function TocEntry(el, text, toclevel) {
  this.element = el;
  this.text = text;
  this.toclevel = toclevel;
  this.assigned = false;

  if (el.id != '') {
    this.id = el.id;

  } else {
    var a = el.firstChild;
    if ((a.tagName == "a" || a.tagName == "A") && a.id != "") {
      this.id = a.id;
    } else {
      this.id = '';
    }
  }
}

function tocEntries(el, toclevels) {
  var result = new Array;
  var re = new RegExp('[hH]([2-'+(toclevels+1)+'])');
  // Function that scans the DOM tree for header elements (the DOM2
  // nodeIterator API would be a better technique but not supported by all
  // browsers).
  var iterate = function (el) {
    for (var i = el.firstChild; i != null; i = i.nextSibling) {
      if (i.nodeType == 1 /* Node.ELEMENT_NODE */) {
        var mo = re.exec(i.tagName)
        if (mo)
          result[result.length] = new TocEntry(i, getText(i), mo[1]-1);
        iterate(i);
      }
    }
  }
  iterate(el);
  return result;
}

// This function does the work. toclevels = 1..4.
function generateToc(toclevels) {
  var simple_re = new RegExp('^[a-zA-Z._ -]{1,}$');
  var entries = tocEntries(document.getElementsByTagName("body")[0], toclevels);
  var usedIds = new Array();

  for (var i = 0; i < entries.length; ++i) {
    var entry = entries[i];
    if (entry.id != "")
      usedIds[entry.id] = entry;
  }

  for (var i = 0; i < entries.length; ++i) {
    var entry = entries[i];
    if (entry.id != "" || !simple_re.exec(entry.text))
      continue;

    var n = entry.text.replace(/ /g, '_').toLowerCase();
    var e = usedIds[n];
    if (e) {
      if (e.assigned)
        e.id = '';
      continue;
    }

    entry.assigned = true;
    entry.id = n;
    entry.element.id = entry.id;
    usedIds[n] = entry;
  }

  for (var i = 0; i < entries.length; ++i) {
    var entry = entries[i];
    if (entry.id == '') {
      entry.id = "toc" + i;
      entry.element.id = entry.id;
    }
  }

  var toc = document.getElementById("toc");
  for (var i = 0; i < entries.length; ++i) {
    var entry = entries[i];
    var a = document.createElement("a");
    a.href = "#" + entry.id;
    a.appendChild(document.createTextNode(entry.text));
    var div = document.createElement("div");
    div.appendChild(a);
    div.className = "toclevel" + entry.toclevel;
    toc.appendChild(div);
  }
}
/*]]>*/
</script>
<title>Gerrit2 Git Replication</title>
</head>
<body>
<div id="header">
<h1>Gerrit2 Git Replication</h1>
<span id="revision">version v2.0.24</span>
<div id="toc">
  <div id="toctitle">Table of Contents</div>
  <noscript><p><b>JavaScript must be enabled in your browser to display the table of contents.</b></p></noscript>
</div>
</div>
<div id="preamble">
<div class="sectionbody">
<p>Gerrit can automatically push any changes it makes to its managed Git
repositories to another system.  Usually this would be configured to
provide mirroring of changes, for warm-standby backups, or a
load-balanced public mirror farm.</p>
<p>The replication runs on a short delay.  This gives Gerrit a small
time window to batch updates going to the same project, such as
when a user uploads multiple changes at once.</p>
<p>Typically replication should be done over SSH, with a passwordless
public/private key pair.  On a trusted network it is also possible to
use replication over the insecure (but much faster) git:// protocol,
by enabling the <tt>receive-pack</tt> service on the receiving system, but
this configuration is not recommended.</p>
</div>
</div>
<h2>Enabling Replication</h2>
<div class="sectionbody">
<p>If replicating over SSH (recommended), ensure the host key of the
remote system(s) is already in the Gerrit user's <tt>~/.ssh/known_hosts</tt>
file.  The easiest way to add the host key is to connect once by hand
with the command line:</p>
<div class="exampleblock">
<div class="exampleblock-content">
<div class="literalblock">
<div class="content">
<pre><tt>sudo su -c 'ssh mirror1.us.some.org echo' gerrit2</tt></pre>
</div></div>
</div></div>
<p>Next, create <tt><em>$site_path</em>/replication.config</tt> as a Git-style config
file, and restart Gerrit.</p>
<p>Example <tt>replication.config</tt> to replicate in parallel to four
different hosts:</p>
<div class="exampleblock">
<div class="exampleblock-content">
<div class="literalblock">
<div class="content">
<pre><tt>[remote "host-one"]
  url = gerrit2@host-one.example.com:/some/path/${name}.git</tt></pre>
</div></div>
<div class="literalblock">
<div class="content">
<pre><tt>[remote "pubmirror"]
  url = mirror1.us.some.org:/pub/git/${name}.git
  url = mirror2.us.some.org:/pub/git/${name}.git
  url = mirror3.us.some.org:/pub/git/${name}.git
  push = +refs/heads/*
  push = +refs/tags/*
  threads = 3</tt></pre>
</div></div>
</div></div>
<p>To manually trigger replication at runtime, see
<a href="cmd-replicate.html">gerrit replicate</a>.</p>
</div>
<h2><a id="replication_config"></a>File <tt>replication.config</tt></h2>
<div class="sectionbody">
<p>The optional file <tt><em>$site_path</em>/replication.config</tt> is a Git-style
config file that controls the replication settings for Gerrit.</p>
<p>The file is composed of one or more <tt>remote</tt> sections, each remote
section provides common configuration settings for one or more
destination URLs.</p>
<p>Each remote section uses its own thread pool.  If pushing to
multiple remotes, over differing types of network connections
(e.g. LAN and also public Internet), its a good idea to put them
into different remote sections, so that replication to the slower
connection does not starve out the faster local one.  The example
file above does this.</p>
<h3><a id="remote"></a>Section remote</h3>
<p>In the keys below, the &lt;name&gt; portion is unused by Gerrit, but must be
unique to distinguish the different sections if more than one remote
section appears in the file.</p>
<dl>
<dt>
<a id="remote.name.url"></a>remote.&lt;name&gt;.url
</dt>
<dd>
<p>Address of the remote server to push to.  Multiple URLs may
be specified within a single remote block, listing different
destinations which share the same settings.  Assuming sufficient
threads in the thread pool, Gerrit pushes to all URLs in parallel,
using one thread per URL.</p>
<p>Within each URL value the magic placeholder <tt>${name}</tt> is replaced
with the Gerrit project name.  This is a Gerrit specific extension
to the otherwise standard Git URL syntax.</p>
<p>See <a href="http://www.kernel.org/pub/software/scm/git/docs/git-push.html#URLS">GIT URLS</a>
for details on Git URL syntax.</p>
</dd>
<dt>
<a id="remote.name.receivepack"></a>remote.&lt;name&gt;.receivepack
</dt>
<dd>
<p>Path of the <tt>git-receive-pack</tt> executable on the remote system, if
using the SSH transport.</p>
<p>Defaults to <tt>git-receive-pack</tt>.</p>
</dd>
<dt>
<a id="remote.name.uploadpack"></a>remote.&lt;name&gt;.uploadpack
</dt>
<dd>
<p>Path of the <tt>git-upload-pack</tt> executable on the remote system, if
using the SSH transport.</p>
<p>Defaults to <tt>git-upload-pack</tt>.</p>
</dd>
<dt>
<a id="remote.name.push"></a>remote.&lt;name&gt;.push
</dt>
<dd>
<p>Standard Git refspec denoting what should be replicated.  Setting this
to <tt>+refs/heads/*:refs/heads/*</tt> would mirror only the active
branches, but not the change refs under <tt>refs/changes/</tt>, or the tags
under <tt>refs/tags/</tt>.</p>
<p>Multiple push keys can be supplied, to specify multiple patterns
to match against.  In the example file above, remote "pubmirror"
uses two push keys to match both <tt>refs/heads/*</tt> and <tt>refs/tags/*</tt>,
but excludes all others, including <tt>refs/changes/*</tt>.</p>
<p>Defaults to <tt>+refs/*:refs/*</tt> (all refs) if not specified.</p>
</dd>
<dt>
<a id="remote.name.timeout"></a>remote.&lt;name&gt;.timeout
</dt>
<dd>
<p>Number of seconds to wait for a network read or write to complete
before giving up and declaring the remote side is not responding.
If 0, there is no timeout, and the push client waits indefinitely.</p>
<p>A timeout should be large enough to mostly transfer the objects to
the other side.  1 second may be too small for larger projects,
especially over a WAN link, while 10-30 seconds is a much more
reasonable timeout value.</p>
<p>Defaults to 0 seconds, wait indefinitely.</p>
</dd>
<dt>
<a id="remote.name.replicationDelay"></a>remote.&lt;name&gt;.replicationDelay
</dt>
<dd>
<p>Number of seconds to wait before scheduling a remote push operation.
Setting the delay to 0 effectively disables the delay, causing the
push to start as soon as possible.</p>
<p>This is a Gerrit specific extension to the Git remote block.</p>
<p>By default, 15 seconds.</p>
</dd>
<dt>
<a id="remote.name.threads"></a>remote.&lt;name&gt;.threads
</dt>
<dd>
<p>Number of worker threads to dedicate to pushing to the repositories
described by this remote.  Each thread can push one project at a
time, to one destination URL.  Scheduling within the thread pool
is done on a per-project basis.  If a remote block describes 4
URLs, allocating 4 threads in the pool will permit some level of
parallel pushing.</p>
<p>By default, 1 thread.</p>
</dd>
</dl>
</div>
<h2><a id="ssh_config"></a>File <tt>~/.ssh/config</tt></h2>
<div class="sectionbody">
<p>If present, Gerrit reads and caches <tt>~/.ssh/config</tt> at startup, and
supports most SSH configuration options.  For example:</p>
<div class="exampleblock">
<div class="exampleblock-content">
<div class="literalblock">
<div class="content">
<pre><tt>Host host-one.example.com:
  IdentityFile ~/.ssh/id_hostone
  PreferredAuthentications publickey</tt></pre>
</div></div>
<div class="literalblock">
<div class="content">
<pre><tt>Host mirror*.us.some.org:
  User mirror-updater
  IdentityFile ~/.ssh/id_pubmirror
  PreferredAuthentications publickey</tt></pre>
</div></div>
</div></div>
<p>Supported options:</p>
<ul>
<li>
<p>
Host
</p>
</li>
<li>
<p>
Hostname
</p>
</li>
<li>
<p>
User
</p>
</li>
<li>
<p>
Port
</p>
</li>
<li>
<p>
IdentityFile
</p>
</li>
<li>
<p>
PreferredAuthentications
</p>
</li>
<li>
<p>
StrictHostKeyChecking
</p>
</li>
</ul>
<p>SSH authentication must be by passwordless public key, as there is
no facility to read passphases on startup or passwords during the
SSH connection setup, and SSH agents are not supported from Java.</p>
<p>Host keys for any destination SSH servers must appear in the user's
<tt>~/.ssh/known_hosts</tt> file, and must be added in advance, before
Gerrit starts.  If a host key is not listed, Gerrit will be unable to
connect to that destination, and replication to that URL will fail.</p>
</div>
<hr style="
  height: 2px;
  color: silver;
  margin-top: 1.2em;
  margin-bottom: 0.5em;
">
<p>Part of <a href="index.html">Gerrit Code Review</a></p>
<div id="footer">
<div id="footer-text">
Version v2.0.24<br />
Last updated 02-Nov-2009 16:31:14 PDT
</div>
</div>
</body>
</html>
